Adhesive cooling composition and process for its preparation

ABSTRACT

The invention provides an adhesive cooling gel composition which stably contains a large amount of water and which is excellent in cooling effect and/or coolness-preserving effect, and a process for preparing the same. The composition comprises a polyacrylic acid compound, a polyvalent metal component and water, wherein the content of water is 75 to 95% by weight based on the cooling composition. Also disclosed are an adhesive cooling composition shaped into a sheet, and a process for preparing the adhesive cooling composition, the process being selected from processes given below in (1) to (3), each process including a step of mixing and dissolving the components of the composition and a deaerating step: (1) a process wherein an aqueous solution is deaerated and then the other components of the composition are mixed and/or dissolved; (2) a process wherein while an aqueous solution is deaerated, the other components of the composition are mixed and/or dissolved; or (3) a process wherein after the other components of the composition are mixed and/or dissolved, the obtained solution is deaerated.

FIELD OF THE INVENTION

1. The present invention relates to an adhesive cooling composition tobe directly or indirectly applied to a subject including humans to coolthe subject due to its latent heat in vaporization of water and aprocess for preparing the composition.

BACKGROUND OF THE INVENTION

2. Conventional cooling bases for a cooling composition include, forexample, gels or aqueous solutions of crosslinked polyethylene glycol(PEG), polyethylene oxide (PEO), polyvinyl alcohol (PVA), sodiumcarboxymethyl cellulose, polyacrylic acid, salts thereof, carboxyvinylpolymer (CVP) or the like.

3. The cooling composition is available in various forms such as a sheethaving a cooling base sealed with a film of polyethylene, polypropyleneor the like or a poultice comprising a non-woven fabric or like fabricscoated with a gel base. In recent years, a demand has been growing forpoultice-type cooling products from the viewpoints of adhesion,fixation, convenience in use, heat-absorbing property and so on.

4. Generally the cooling base for use in such poultice-type coolingproducts are in the form of a gel which is superior in shape retentivityand adhesiveness. For this reason, it is very difficult to uniformlystir and knead the components of the cooling composition in themanufacture thereof. Because of this difficulty, there arise problems,for example, masses of components not dispersed well due to insufficientstirring and air bubbles incorporated into the gel base.

5. Attempts have been made in the art to overcome such problems using anorganic solvent such as polyhydric alcohol in more than a specificamount to reduce the dispersion density of the base.

6. However, this method, although advantageous in giving a uniform gelcomposition, inevitably involves a decrease of water to be incorporatedinto the composition in an amount corresponding to the volume of theorganic solvent, consequently failing to produce a cooling compositionwhich can achieve a higher cooling effect.

SUMMARY OF THE INVENTION

7. The present invention was completed in view of the above situation.

8. It is an object of the present invention to provide an adhesivecooling composition in a gel form which stably contains a large amountof water and which is excellent in cooling effect and/orcoolness-preserving effect.

9. The adhesive cooling composition of the invention is safelyapplicable without causing irritation to the subject to be cooled,especially human's skins. The composition which is adhesive by itselfcan be conveniently fixed to a substrate (a subject to be cooled,including humans) without use of an aid such as an adhesive tape. Afurther advantage is that even when directly applied to the surface of asubstrate, preferably to human's skins, the composition can be removedwithout leaving any residue on the substrate.

10. It is another object of the invention to provide a process forpreparing the foregoing adhesive cooling composition.

11. It is a further object of the invention to provide an adhesivecooling device in the form of a sheet which contains the above-mentionedcooling composition as a cooling base.

12. The present inventors conducted extensive research to prepare auniform gel composition without giving masses of components notdispersed well due to insufficient stirring, when mixing a polyacrylicacid, a polyvalent metal and an aqueous solution. As a result, theinventors found that when the bubble component is removed from theaqueous solution by deaeration, stirring and kneading can be done withan improved efficiency and the components can be uniformly dispersed inthe aqueous solution, whereby a uniform gel composition is obtained. Thegel composition produced by this method has the components dispersedwell in the aqueous solution and is uniform and substantially free of abubble component, even if a conventional solvent such as polyhydricalcohol is used in a considerably low proportion to the aqueous solution(or even if such solvent is not used).

13. The adhesive cooling composition of the invention need not contain asolvent, e.g. polyhydric alcohol as an essential constituent (or it maycontain a small amount of a solvent) and is free of air bubbles. Due tothe absence of a solvent and freedom from air bubbles, a more amount ofwater can be accommodated in the cooling composition.

14. Based on the above-mentioned findings, the present inventorsrealized at once the increase of water content conventionally considereddifficult, directing attention to both the production process and theformula and successfully developed an adhesive cooling compositionhaving a high cooling effect.

BRIEF DESCRIPTION OF THE DRAWINGS

15.FIG. 1 is a graph showing the results of measuring the caloriesconsumed by Plaster A of the invention (A in the graph) and by Plaster Bof the invention (B in the graph) in Experiment Example 1. The lapse oftime (hr) is plotted as the abscissa and the calorie(×10⁻⁴(cal/cm²·sec·°C.) required to keep the hot plate constant at 37°C. was plotted as the ordinate.

16.FIG. 2 shows the results, in comparison, of Kraepelin test carriedout in the presence or absence of lavender fragrance in ExperimentExample 4 (1).

17.FIG. 3 is a graph showing the amount of α wave appearing when theplaster of the invention was used in Experiment Example 4 (2), comparedwith the case wherein the plaster thereof was not used. A graph A inFIG. 3 shows a detailed distribution of a wave at 8 to 13 HZ which wasobtained by the analysis of electroencephalogram (EEG) at 8 to 13 HZ. Agraph B in FIG. 3 shows the overall amounts of α wave appearing, incomparison between the data in the presence or absence of the plaster ofthe invention. A graph C in FIG. 3 shows the proportions of α wave inthe EEG in its entirety (including the EEG outside 8-13 HZ region) incomparison between the data in the presence or absence of the plaster ofthe invention.

18.FIG. 4 shows an increase in the temperature of peripheral skinbrought about by application of the plaster of the invention inExperiment Example 4 (3). A graph A in the figure shows the results ofmeasuring the temperature of peripheral skin before rest (3 minutes, adotted line) and after rest (for 3 minutes, a solid line) withoutapplication of the plaster of the invention. A graph B shows the resultsof measuring the temperature of peripheral skin before rest (3 minutes,a dotted line) without application of the plaster of the invention andafter rest (3 minutes, a solid line) with the plaster of the inventionapplied.

DETAILED DESCRIPTION OF THE INVENTION

19. The adhesive cooling composition of the present invention comprisesat least a polyacrylic acid compound, a polyvalent metal component andwater, and the composition is characterized in that the compositioncontains water in an amount of 75 to 95% by weight based on the coolingcomposition.

20. The term “polyacrylic acid compound” used herein includes salts ofpolyacrylic acids as well as polyacrylic acids.

21. Polyacrylic acids and salts of polyacrylic acids are usableirrespective of straight chain or branched chain form. The molecularweight of a polyacrylic acid compound to be used is not limited. Usuallyit has a molecular weight of 10,000 to 10,000,000. From the viewpoint ofincreasing the gel strength for the composition to stably hold morewater, it is desirable to use a polyacrylic acid compound having amolecular weight of 1,000,000 to 7,000,000, preferably 4,000,000 to6,000,000 (as determined by gel permeation chromatography (GPC)).

22. Suitable examples of the polyacrylic acid compound include partiallycrosslinked acrylic acid polymers (e.g. “Carbopol” (registeredtrademark), product of BF Goodrich Chemical Co.) as well as conventionalpolymers prepared by polymerization of acrylic acid.

23. Useful salts of polyacrylic acids are not limited. Preferred aremonovalent metal salts of polyacrylic acids such as sodium polyacrylate,potassium polyacrylate and the like; amine polyacrylates such asmonoethanolamine polyacrylate, diethanolamine polyacrylate,triethanolamine polyacrylate and the like; and ammonium salts ofpolyacrylic acids. These salts of polyacrylic acids can be used eitheralone or in combination. More preferred are alkali metal salts ofpolyacrylic acids such as sodium polyacrylate.

24. The above-mentioned polyacrylic acids and salts of polyacrylic acidscan be used either alone or in combination. Generally the polyacrylicacid compound having a molecular weight of at least 1,000,000 is noteasily available. Consequently it is desirable to use polyacrylic acidsand salts of polyacrylic acids (such as sodium polyacrylate) incombination. However, if a polyacrylic acid compound with a molecularweight of at least 1,000,000 becomes easily available in future, thecombined use would become unnecessary.

25. When the polyacrylic acid and a salt thereof are used incombination, their ratio is not limited insofar as the ratio is adjustedso that the combination has a molecular weight of at least 1,000,00,preferably at least 2,000,000, more preferably at least 4,000,000. Theratio (weight ratio) is, for example, in the range of from 0:10 to 9:1,preferably from 2:1 to 1:2.

26. The amount of the polyacrylic acid and/or a salt thereof used is 1to 20% by weight, preferably 3 to 10% by weight, based on the coolingcomposition.

27. The term “polyvalent metal component” is used herein to include abroad range of species including polyvalent metals, salts thereof andpolyvalent metal compounds.

28. The polyvalent metal component is not limited insofar as it has atleast two valences and are capable of crosslinking the above-mentionedpolyacrylic acids and/or salts of polyacrylic acids. The compounds asthe polyvalent metal component can be used either alone or incombination.

29. Suitable examples of the polyvalent metal component are magnesium,calcium, zinc, cadmium, aluminum, titanium, manganese, cobalt, nickeland like polyvalent metals, their salts and their compounds. From theviewpoints of safety for skins, productivity and gel characteristics, itis preferred to use aluminum, magnesium, calcium or their compounds.Especially preferred are aluminum compounds.

30. Examples of useful aluminum compounds are hydroxides such asaluminum hydroxide; normal salts of inorganic or organic acids such asaluminum chloride, aluminum sulfate, aluminum acetate and aluminumstearate; basic salts thereof; double salts such as aluminum alum andpotassium alum (potassium aluminum sulfate); aluminates such as sodiumaluminate; inorganic aluminum complex salts; and organic aluminumchelate compounds. These aluminum compounds may be either soluble inwater or sparingly soluble in water.

31. Useful magnesium compounds are, for example, magnesium hydroxide,magnesium carbonate, magnesium sulfate, magnesium nitrate, magnesiumchloride and magnesium acetate. Useful calcium compounds are, forexample, calcium hydroxide, calcium carbonate, calcium sulfate, calciumnitrate, calcium chloride, calcium acetate, calcium oxide and calciumphosphate.

32. The amount of the polyvalent metal component used is 0.01 to 20% byweight, preferably 0.01 to 10% by weight, more preferably 0.05 to 1% byweight, most preferably 0.1 to 0.5% by weight, based on the coolingcomposition.

33. The adhesive cooling composition of the invention contains water inaddition to the above-mentioned components. The amount of water used is75 to 95% by weight, preferably 81 to 95% by weight, more preferably 81to 90% by weight, most preferably 81 to 85% by weight, based on thecooling composition.

34. The adhesive cooling composition of the invention is capable ofgradually vaporizing water from the surface of the gel with time, and istherefore always maintained at a lower temperature than room temperaturedue to its latent heat, i.e. heat radiated in the vaporization of water.Consequently when the composition is applied to a subject, the subjectis deprived of heat because of its latent heat of vaporization and isthereby cooled. In other words, the water contained in the compositionis a source of cooling activity. Thus, the higher the water content is,the higher the cooling effect is.

35. The adhesive cooling composition comprising the above-mentionedcomponents is in the form of a high molecular elastic gel, and is likelyto contain air bubbles. The presence of such bubble component in thecomposition reduces the amount of water to be held by the compositionper volume unit. Therefore, desirably the cooling composition of theinvention is substantially free of a bubble component.

36. As described later in Experiment Example 1, when the coolingcomposition of the invention is substantially free of a bubblecomponent, the composition can achieve a higher cooling effect,especially a higher quenching effect than compositions containing abubble component, and is therefore very useful in fulfilling a quenchingpurpose.

37. The term “bubble component” used herein refers to a wide range ofair bubbles including bubble gases as well as visually recognizable airbubbles.

38. The expression “substantially free of a bubble component” usedherein means the absence of a bubble or the presence of a few bubbles,more specifically refers to a state in which no bubble is visuallyobservable and no trace of broken bubbles exists on the surface of thegel or on the surface of a cut portion after processing the coolingcomposition.

39. The adhesive cooling composition of the invention comprises theabove-mentioned components, and optionally may further contain at leastone member selected from the group consisting of tartaric acid, citricacid, phosphoric acid, ethylenediaminetetraacetic acid and saltsthereof.

40. These acids or salts thereof are useful for the following advantage.When combined with a polyvalent metal component, they can adjust the pHof the composition and can control the liberating rate (dissociation) ofmetal ions to bring the gel strength (crosslinking degree) to thedesired range. Tartaric acid is preferred among them.

41. The amount of the foregoing acid or salt thereof used is suitablyselected from the range of 0.01 to 5% by weight, preferably 0.05 to 0.5%by weight, based on the cooling composition.

42. Optionally the adhesive cooling composition of the invention mayfurther contain a polyhydric alcohol. Polyhydric alcohols are useful asa dispersing medium for polyacrylic acid or salts thereof, or as abinder in dispersing and/or emulsifying in water an oil component suchas 1-menthol or the like, and are usable in moisturizing the compositionand improving the comfortableness in use.

43. Polyhydric alcohols are not limited in terms of linear or branchedchain form and molecular weight and can be any of species usually usedwhich are safe for subjects. Examples are glycerin, ethylene glycol,diethylene glycol, triethylene glycol, polyethylene glycol, propyleneglycol, butylene glycol, polypropylene glycol, 1,3-propanediol,1,4-butanediol, maltitol, xylitol and sorbitol. Among them, glycerin,propylene glycol and butylene glycol are suitable to use.

44. The amount of the polyhydric alcohol used is suitably selected fromthe range of 0.001 to 30% by weight, preferably 5 to 20% by weight, morepreferably 10 to 20% by weight, based on the cooling composition. Theuse in an amount of less than 0.5% by weight is limitless.

45. Optionally the adhesive cooling composition of the invention maycontain a cellulose derivative.

46. The cellulose derivative is useful in improving the processabilityof the composition of the invention which is a non-Newtonian fluid, inenhancing the stability of the gel and in facilitating the adjustment ofviscosity.

47. There is no limitation on the cellulose derivatives to be used.Specific examples are carboxymethyl cellulose, hydroxymethyl cellulose,hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, andalkali metal salts (sodium, potassium or the like) thereof and the like.These cellulose derivatives can be used either alone or in combination.Among them, carboxymethyl cellulose and alkali metal salts thereof arepreferred.

48. The amount of the cellulose derivative used is suitably selectedfrom the range of 0.01 to 10% by weight, preferably 0.1 to 5% by weight,more preferably 0.1 to 0.45% by weight, based on the coolingcomposition.

49. The adhesive cooling composition of the invention contains, asdescribed above, water in a high proportion of at least 75% by weightbased on the cooling composition, and therefore is excellent inheat-absorbing effect.

50. The adhesive cooling composition of the invention can stably hold alarge amount of water and is not caused to ooze the water whencompressed. Even if the composition has a water content of as high as95% by weight, it is not rendered flowable when its viscosity isreduced, namely has an advantage of having shape retentivity. Thecomposition even with a high water content is suitably elastic andhighly adhesive and has a feature of being limitless in terms ofsubjects and locations to be applied.

51. The adhesive cooling composition of the invention is advantageous inthat it is easily removable from any subjects without leaving anyresidue on the subject and is highly safe.

52. Optionally the adhesive cooling composition of the invention mayfurther contain a perfume such as peppermint oils, 1-menthol, linalooland linalyl acetate, antiseptics, humectants, irritation-relaxingagents, antimicrobial agents and the like.

53. A suitable adhesive cooling composition of the invention preferablycontains at least one of linalool or linalyl acetate as a perfume inaddition to the above components.

54. Any of linalool species extensively naturally occurring can be usedirrespective of difference in structural isomers and in d-form orl-form. Preferred linalool is l-linalool, such as one in a lavender oil.The linalyl acetate to be used can be any of the species extensivelynaturally occurring. These perfumes are not limited in terms of theorigin.

55. The amount of the linalool used is 0.0005 to 0.6% by weight,preferably 0.002 to 0.45% by weight, more preferably 0.003 to 0.4% byweight, based on the cooling composition obtained as the end product.

56. The amount of the linalyl acetate used is 0.0005 to 0.8% by weight,preferably 0.002 to 0.7% by weight, more preferably 0.003 to 0.6% byweight, based on the cooling composition obtained as the end product.

57. The adhesive cooling composition of the invention may contain thesecomponents individually or as a mixture.

58. Among linalool species, d-linalool is contained in refined oils suchas linaloe oils of Mexican growth, roosewood oils, coriander oils orOrth. linalooliferum Fujita, and l-linalool is contained in refined oilssuch as hosho oils, lavender oils or bergamot oils. Linalyl acetate iscontained in refined oils such as lavender oils, bergamot oils,petigrain oils, jasmine oils, ylan-ylan oils or lemon oils. Consequentlythese refined oils can be used as linalool or linalyl acetate insofar asthey do not adversely affect the contemplated effect of the invention.

59. Lavender oils are suitable as such refined oils. Lavender oilscontain, in addition to linalyl acetate and 1-linalool, hundreds ofcomponents such as geraniol, lavandulol, nerol, α-pinene, caryophyllene,1,8-cineole, camphene, 1-limonene and dipennene. These components of thelavender oils are considered to cooperatively act for achieving theeffect of the invention without adversely affecting the effect thereof.

60. Generally the lavender oil can be prepared, for example, bysubjecting the flower ear of lavender to steam distillation or byextraction using a solvent such as hexane, petroleum ether, alcohol orthe like.

61. The adhesive cooling composition of the invention may contain atleast one of the lavender extracts prepared as above.

62. Lavenders usable in the invention are selected from a wide range ofspecies including those pertaining to the genus Perilla frutescenscrispd and their variety. Generally lavenders are classified as givenbelow according to the shape of leaves and bracts:

63. (1) Spica-type lavender group, (2) Stoechas-type lavender group, and(3) Fern-like lavender group (Pterostachys lavender). The lavender group(1) is sub-classified into Lavandula angustifolia Mill. speciesincluding their agricultural species, Lavandin type (L.x intermediaEmeric ex Loisel. (Lavandula hybrida Reverchon ex Briq., L. hortensisHy)) and others (e.g. L. latifolia Medik. (L. spica auct., non L.)). Anyof these lavenders can be used in the invention.

64. There is no limitation on lavenders in terms of the origin and thegeographical region of growth. Useful lavenders can be any of thosegrown, e.g. in France, Italy, U.K., Russia, Australia, North America andJapan (Hokkaido).

65. Lavender extracts useful in the invention are not limited in termsof other components in the extract and their proportions insofar as theextract contains 5 to 60% by weight, preferably 20 to 45% by weight, oflinalool or 5 to 80% by weight, preferably 20 to 70% by weight, oflinalyl acetate.

66. It is desirable that the adhesive cooling composition of theinvention contain 0.01 to 1% by weight, preferably 0.05 to 0.5% byweight, more preferably 0.1 to 0.3% by weight, of such lavender extractwhich, however, is not limitative.

67. The adhesive cooling composition of the invention containing any ofthese perfumes may further contain a surfactant. The surfactant to beused in the invention is suitably selected from any kind of surfactantsincluding cationic, anionic, amphoteric and nonionic surfactantscommonly used, according to the type of linalool or linalyl acetate tobe contained in the composition of the invention and the type of perfumecomponents of refined oils. These surfactants can be used either aloneor in combination.

68. The adhesive cooling composition of the invention containing aperfume such as linalool or linalyl acetate can be effectively usedespecially for mammal animals including humans because of theirundermentioned activities as well as the above-mentioned coolingactivity.

69. When the adhesive cooling composition of the invention is directlyor indirectly applied or pasted to the human body, the components oflavender extract such as linalool or linalyl acetate in the compositionvaporize and effectively act through the nasal cavity, whereby the nerveis relaxed and the blood flow of peripheral skin is increased to elevatethe temperature of peripheral skin, thereby promoting the radiation ofheat from the inside of the body.

70. It is known that a specific correlation exists between the bodytemperature and sleep rhythm. Stated more specifically, the temperatureof peripheral skin begins to rise just before falling asleep and alittle later the rectal temperature is lowered. This state is retainedduring sleep (“Sogo Rinsho” vol.34, Special Number (1985), 14-16). It issuggested that the occurrence of body temperature rhythm just beforefalling asleep involves the mechanism for increasing the blood flow ofskin to radiate the heat from the inside of the body. (Damm, F., Doring,G., et al “Body Temperature and Circadian Rhythm” 1973).

71. When the adhesive cooling composition of the invention is used,human biorhythm is artificially made close to natural body temperaturerhythm in the beginning of sleep, whereby more natural sleep can beinduced. The adhesive cooling composition of the invention allows thewater held therein to evaporate from the surface with time as describedabove, and absorbs heat due to latent heat involved in vaporization. Ifthe composition is applied or pasted to the skin before sleep, the skinis deprived of heat owing to latent heat of vaporization. Thecomposition can promote the subject's activity of radiating heat fromthe body to smoothly induce sleep.

72. When the adhesive cooling composition of the invention is used,vaporizable components of lavender such as linalool or the like cantranquilize the subject when vaporized owing to the body temperature,namely can mentally assist the subject in inducing a peaceful sleep.

73. The adhesive cooling composition of the invention can be used toeffectively act against insomnia or sleep-hindering trouble which iscaused by mental factors such as anxiety, overwork, melancholy,excitement or the like, or by the irregularity of biorhythm.

74. The adhesive cooling composition of the invention can be prepared bya process comprising a step of mixing and/or dissolving the componentsof the composition and a deaerating step.

75. The mixing and/or dissolving step and the deaerating step are notlimited in terms of the order and can be carried out in any order. Forexample, (i) before the components of the composition are mixed and/ordissolved, water or an aqueous solution may be deaerated; (ii) whilewater or an aqueous solution is deaerated, the other components of thecomposition are mixed with and/or dissolved in water or aqueoussolution; or (iii) after the other components of the composition aremixed with and/or dissolved in water or an aqueous solution, theobtained solution is deaerated. When the composition containsvaporizable components, the process (i) or (ii) is preferred among theseprocesses, and the process (i) is more preferred. In the case of theprocess (i) or (ii), after all of the components are added, they can bedeaerated again in mixing them with stirring.

76. The deaeration method is not limited and is variously selectedaccording to the subject to be treated and the treating stage. To avoidthe increase of dispersion density of a solvent, it is preferred toconduct physical deaeration such as deaeration by mesh filtration andvacuum deaeration. The vacuum deaeration can be carried out, forexample, by a closed vacuum method using a vacuum pump or a stirrer witha vacuum pump.

77. Stated more specifically, deaeration may be conducted, for example,using a stirrer with a vacuum pump at about 700 mmHg and at about 20 toabout 30° C. for about 30 minutes for 1 liter of water or an aqueoussolution-used to which, however, the deaeration is not limited.

78. The method of stirring and kneading a solvent or an aqueous solutionin the composition is not limited and can be carried out in theconventional manner, preferably using a twin-screw universal kneader, atwin-screw planetary mixer or equivalents thereof. These devices can beused over a wide range of stirring capability which enables theformation of low to high viscosity mass, and can satisfactorily copewith a rapid increase of viscosity occurring, e.g. in mixing a solventsystem and an aqueous system. The devices are also beneficially operablewithout breakage of a gel by stirring and kneading on or after theformation thereof.

79. The adhesive cooling composition of the invention can be used mainlyto partly cool the body part which is not limitative. For example, thecomposition can be applied to the forehead of a subject who is feverish,can cool body parts such as eyes, cheeks, jaws, legs, feet and the likewhich are locally in fever, or can cool inflammatory parts to assuagethe pain when suffering from blow pain, sprain or muscular pain.

80. In application of the adhesive cooling composition of the inventioncontaining a perfume such as linalool or the like, the vaporizablecomponents of lavender are caused to act through the nasal cavity forthe promotion of sleep inducement. For this purpose, the composition ispreferably applied to body parts such as the upper half part in theneighborhood of the nose, preferably the breast or face and head,particularly the forehead.

81. According to the invention, there is also provided a cooling device(cooling article) which is produced by shaping the composition into aproduct in a specific shape according to the purpose of topicalapplication.

82. While the cooling device is not limited in terms of a shape, alaminated sheet is preferred because it is easy to handle, portable andstorageable. The laminated sheet can be produced by spreading the gelcomposition of the invention into a sheet or by applying the gelcomposition to a moisture-permeable sheet and spreading the composition.The latter form, i.e. a laminate sheet of a layer of gel compositionlaminated on a moisture-permeable sheet, is preferred from theviewpoints of handleability and convenient use.

83. There is no restriction on moisture-permeable sheets insofar as theycan support the adhesive cooling composition and they have such suitablegas moisture permeability that they do not hinder the passage of a gasand vapor according to the moisture-releasing property of thecomposition and the vapor transmission of vaporizable components of aperfume such as linalool. Examples of useful sheets include variouswoven fabrics, non-woven fabrics and films. Insofar as the sheet hassaid properties, the pore diameter of the sheet is not limited, and isabout 0.001 to about 5 mm, preferably about 0.01 to about 1 mm.

84. When the substrate is made of woven fabrics or non-woven fabrics,the raw materials thereof are not limited. Specific examples are naturalfibers such as cotton, flax, wool and the like; cellulose fibers such asrayon, acetate and the like; and synthetic fibers such as nylon,vinylon, styrol, polypropylene, polyethylene, polyethyleneterephthalate, acryl and the like.

85. When a film is used as the substrate, the raw materials are notlimited. Examples are styrol, polypropylene, polyethylene terephthalateand polyethylene. A mesh film can be used to assure suitablepermeability and moisture-permeability. The pore diameter of the meshfilm is not limited but is 0.001 to 5 mm, preferably 0.01 to 1 mm asdescribed above.

86. The thickness of the moisture-permeable substrate is not limitedinsofar as it does not hinder the passage of a vapor based on themoisture-releasing property of the composition. The thickness is 1 to1000 μm, preferably 10 to 500 μm from the viewpoints of convenience inuse and amenability to the site of application.

87. It is desirable that the substrate have suitable elasticitysufficient to become amenable to the external shape at the site ofapplication on application of the cooling device to the skin.

88. The thickness of the adhesive cooling composition laminated on themoisture-permeable substrate is not limited, and is 10 to 10,000 μm,preferably 500 to 5,000 μm, more preferably 1,000 to 4,500 μm from theviewpoints of convenience in use, the amount of heat absorption and thelike.

89. The amount of the composition to be laminated is not limited. It isdesirable to apply and spread 50 to 200 g, preferably 100 to 150 g, ofthe composition per square meter of the moisture-permeable substrate.

90. The laminated sheet of the invention basically comprises acombination of the adhesive cooling composition and a moisture-permeablesubstrate, and optionally has a peelable film laminated on the surfaceof the adhesive cooling composition sheet. The peelable film is removedbefore use for the handleability and hygiene.

91. Such peelable film may be made of polyester, polypropylene,polyethylene, nylon, vinyl chloride, polyethylene terephthalate or thelike.

92. The laminated sheet of the invention is not limited in terms ofexternal shape (size and the like) and has an external shape (size andthe like) suitably selected according to the subject, the site ofapplication and the like.

93. The laminated sheet of the invention can be produced by conventionalmethods using the adhesive cooling composition prepared in theabove-mentioned manner. For example, the composition of the invention isuniformly spread on a peelable sheet to form a layer, and themoisture-permeable sheet is superposed on the layer. In this case, thelaminated mass may be compressed by a roller to strengthen the fixation.

94. The laminated sheet of the invention not only can be applied to theforehead of a subject who is feverish, but also can be used as a device(article) for cooling body parts such as eyes, cheeks, jaws and otherface portions, legs, feet and the like which are in fever. The laminatedsheet also can temporarily cool body parts of inflammation caused byblow or sprain. The sheet can be used to cool down the muscles afterplaying sports. The sheet is useful also because it is immediatelyapplicable without trouble and is disposable.

95. The laminated sheet of the invention prepared from the compositioncontaining a perfume such as linalool and the like can absorb heat fromthe surface of skin and is useful as an aid or a sleep inducementpromoting device capable of inducing sleep smoothly.

EXAMPLES

96. The present invention is described below in more detail withreference to the following examples, comparative examples and experimentexamples to which, however, the invention is not limited.

Example 1

97. The adhesive cooling composition of the invention was preparedaccording to the following formula. Sodium polyacrylate 7 w/w %(molecular weight 5,000,000) Potassium alum 0.2 Deionized water 92.8 100w/w %

98. Production Method

99. 1. Deionized water (0.928 liter) was placed into a stirring kneaderand was vacuum-defoamed using a mixer with a vacuum-defoaming abilityfor about 30 minutes (about 30° C.).

100. 2. Sodium polyacrylate and potassium alum were mixed and were addedto the kneader described above in item 1 while the mixture was stirredand kneaded in a manner to avoid the formation of powder masses.

101. 3. After addition, while the mixture was vacuum-defoamed, stirringand kneading were carried out for an optional time until the bubblecomponent was substantially lost.

102. No bubble component was visible in the obtained adhesive coolingcomposition and no trace of bubble was found on the surface of a cutportion of the cooling device of the composition.

Example 2

103. The adhesive cooling composition of the invention was preparedaccording to the following formula. Sodium polyacrylate 7 w/w %(molecular weight 5,000,000) Aluminum hydroxide 0.2 Tartaric acid 0.3Deionized water 92.5 100 w/w %

104. Production Method

105. 1. Deionized water (0.925 liter) was placed into a stirring kneaderand tartaric acid was added. The mixture was vacuum-defoamed using amixer with a vacuum-defoaming ability for about 30 minutes (about 30°C.).

106. 2. Sodium polyacrylate and aluminum hydroxide were mixed and wereadded to the kneader described above in item 1 while the mixture wasstirred and kneaded in a manner to avoid the formation of powder masses.

107. 3. After addition, while the mixture was vacuum-defoamed, stirringand kneading were carried out for an optional time until the bubblecomponent was substantially lost.

108. No bubble component was visible in the obtained adhesive coolingcomposition and no trace of bubble was found on the surface of a cutportion of the cooling device of the composition.

Example 3

109. The adhesive cooling composition of the invention was preparedaccording to the following formula. Sodium polyacrylate 5 w/w %(molecular weight 5,000,000) Aluminum hydroxide 0.2 Tartaric acid 0.25Concentrated glycerin 10 Deionized water 84.55 100 w/w %

110. Production Method

111. 1. Sodium polyacrylate, aluminum hydroxide and concentratedglycerin were placed into a stirring kneader and uniformly dispersed.

112. 2. A solution of tartaric acid in deionized water was graduallyadded to the kneader described above in item 1 while the mixture wasstirred and kneaded.

113. 3. After addition, while the mixture was vacuum-defoamed using amixer with a vacuum-defoaming ability, stirring and kneading werecarried out (about 30° C.) for an optional time until the bubblecomponent was substantially lost.

114. No bubble component was visible in the obtained adhesive coolingcomposition and no trace of bubble was found on the surface of a cutportion of the cooling device of the composition.

Example 4

115. Each of the adhesive cooling compositions prepared in Examples 1 to3 was spread over a piece of flannel, non-woven fabric or cloth, was cutinto a suitable size and was sealed into a bag made of aluminum to givea sheet of adhesive cooling composition.

116. No bubble component was visible in the adhesive cooling device thusprepared, or no trace of bubble was found on the surface of a cutportion of the sheet of the composition.

Example 5

117. An adhesive cooling composition was prepared according to the sameformula by the same process as in Example 3 with the exception of notcarrying out the vacuum deaeration in the process.

118. A bubble component was visible in the adhesive cooling compositionthus prepared, or a trace of broken bubbles was found on the gel and atrace of bubbles on the surface of a cut portion of the cooling deviceof the gel composition.

Example 6

119. The adhesive cooling composition of the invention was preparedaccording to the following formula. The amounts of the components shownin the formula are those of the final composition obtained afterdeaeration (the same in subsequent examples). Sodium polyacrylate 6 w/w% (molecular weight 5,000,000) Aluminum hydroxide 15 Tartaric acid 0.3Methylparaben 0.2 Natural perfume 0.5 (Refined oil of common lavender)Deionized water 78.0 100 w/w %

120. Production Method

121. 1. Deionized water and tartaric acid were placed into a stirringkneader and dissolved.

122. 2. Sodium polyacrylate, aluminum hydroxide, methylparaben andlavender were mixed and were added to the kneader described above initem 1 in a manner to avoid the formation of powder masses.

123. 3. After addition, the mixture was vacuum-defoamed for a fewminutes.

Example 7

124. The adhesive cooling composition of the invention was preparedaccording to the following formula. Sodium polyacrylate 5 w/w %(molecular weight 5,000,000) Aluminum hydroxide 0.2 Tartaric acid 0.25Concentrated glycerin 10.0 Natural perfume 0.1 (refined oil of lavender)(Linalool 20% Linalyl acetate 50% Other refined oil 30%) componentsDeionized water 84.45 100 w/w %

125. Production Method

126. 1. Deionized water and tartaric acid were placed into a stirringkneader and dissolved.

127. 2. Sodium polyacrylate, aluminum hydroxide and lavender extractwere mixed with concentrated glycerin.

128. 3. The mixture obtained above in item 1 was gradually added to themixture obtained above in item 2.

129. 4. After addition, the mixture was vacuum-defoamed for a fewminutes.

Example 8

130. The adhesive cooling composition of the invention was preparedaccording to the following formula. Sodium polyacrylate 7 w/w %(molecular weight 5,000,000) Aluminum hydroxide 0.2 Tartaric acid 0.3Synthetic perfume (lavender) 0.3 (Linalool 25% Linalyl acetate 45% Otherrefined oil 30%) components Deionized water 92.2 100 w/w %

131. Production Method

132. 1. Deionized water and tartaric acid were placed into a stirringkneader and dissolved.

133. 2. Sodium polyacrylate, aluminum hydroxide and lavender extractwere mixed together and were added to the kneader described above initem 1 in a manner to avoid the formation of powder masses.

134. 3. After addition, the mixture was vacuum-defoamed for a fewminutes.

Example 9

135. The adhesive cooling composition of the invention was preparedaccording to the following formula. Sodium polyacrylate 7 w/w %(molecular weight 5,000,000) Polyvinyl alcohol 10 Carboxyvinyl polymer 3Aluminum hydroxide 0.2 Tartaric acid 0.2 Synthetic perfume 0.2 (refinedoil of lavender) (Linalool 35% Linalyl acetate 40% Other refined oil30%) components Methylparaben 0.1 Glycerin 5.0 Deionized water 74.3 100w/w %

136. Production Method

137. 1. Deionized water, carboxyvinyl polymer, polyvinyl alcohol andtartaric acid were placed into a stirring kneader and dissolved.

138. 2. Sodium polyacrylate, aluminum hydroxide, lavender andmethylparaben were mixed with glycerin.

139. 3. The mixture obtained above in item 2 was added to the kneaderdescribed above in item 1 in a manner to avoid the formation of powdermasses.

140. 4. After addition, the mixture was vacuum-defoamed for a fewminutes.

Examples 10 to 13

141. The adhesive cooling compositions prepared in Examples 6 to 9(corresponding to Examples 10 to 13, respectively) were spread on ameshy substrate sheet (made of PET) of 0.1 to 1 mm in pore size, werecut to a suitable size (5×13 cm) and were sealed into a bag made ofaluminum to give a laminated sheet (plaster).

EXPERIMENT EXAMPLES Experiment Example 1

142. The adhesive cooling composition prepared in Example 3 was spreadon a non-woven fabric piece in an amount of 125 g per square meter ofthe piece and was cut to a size (3 cm×3 cm) to produce a laminated sheet(Plaster A). Using the composition prepared in Example 5, a laminatedsheet was produced in the same manner (Plaster B).

143. The obtained plasters were pasted to a hot plate at 37° C. and acalorie required to maintain the hot plate at a specific temperature(37° C.) was measured with time. The results of Plaster A (presentinvention) are shown in FIG. 1A and the results of Plaster B (presentinvention) in FIG. 1B. The results show that both plasters produced acooling effect. It was found that Plaster A free of a bubble componentand with a higher water content per volume unit was superior inquenching effect.

Experiment Example 2

144. Plasters A and B used in Experiment Example 1 were fixed on theforeheads of 6 monitors. Then the temperature drop in the foreheads wasmeasured and an average value was calculated. The results are shown inTable 1. TABLE 1 0.5 hr. 1.0 hr. 1.5 hr. 2.0 hr. 2.5 hr. PL. A 2.95° C.2.82° C. 2.95° C. 2.53° C. 2.46° C. PL. B 2.28° C. 1.85° C. 1.75° C.1.08° C. 0.38° C.

145. These results reveal that Plaster A free of a bubble component issuperior in cooling effect to Plaster B containing a bubble component.

Experiment Example 3

146. Three persons were selected at random as the subject from adultswho were wakeful and suffered from insomnia. The laminated sheet(plaster) prepared in Example 10 was applied to their foreheads beforesleep. The test investigated how the plaster affected their sleep.

147. The sleep-inducing effect was evaluated according to the following5-grade criteria. The evaluation was made compared with the subject'ssleep-inducing level before application of the plaster.

148. Evaluation in Terms of Comfortable Sleep (evaluation as to whetherthe subject felt himself or herself having or not having a comfortablesleep or the like)

149. 1. Felt having a comfortable sleep,

150. 2. Felt having some sleep,

151. 3. Hard to say which,

152. 4. Felt having a little sleep,

153. 5. Felt having no sleep.

154. The results are shown in Table 2.

155. Evaluation in Terms of Falling Asleep

156. 1. Falling asleep easily,

157. 2. Falling asleep relatively easily,

158. 3. Hard to say which,

159. 4. Not falling asleep easily,

160. 5. Not falling asleep

161. The results are shown in Table 2. TABLE 2 Evaluation (1) (2) (3)(4) (5) Good sleep 1 2 0 0 0 (Number of person) Falling asleep 1 2 0 0 0(Number of person)

162. As apparent from the results in Table 2, when the plasters of theinvention were used, a high sleep-inducing effect was achieved on any ofsubjects.

Experiment Example 4

163. Tests (1) to (3) given below were carried out to investigate themental stability ((1) Kraepelin test, (2) checking an EEG) and theelevated temperature of peripheral skin which may have occurred when thesubject was exposed to lavender fragrance and when the plasters of theinvention were used.

164. (1) Kraepelin Test

165. Subjects were made to continuously carry out calculation tests.Thereafter the calculation efficiency and change of correctness ratiowere investigated to evaluate the mental stability effect. Two groups ofsubjects were formed, each group consisting of 15 healthy adults aged 24to 32. The group A was made to perform the following calculatory task ina chamber which was filled with a lavender smell given off at roomtemperature from a sheet of paper impregnated with refined oil oflavender. The group B was made to conduct the same calculation tests inan odorless chamber.

166. Calculation Tests

167. The subjects were made (i) to add up two adjacent figures in rowsof figures printed on both surfaces of a piece of paper, and (ii) towrite with a pencil the answer into a space between the two adjacentfigures below each row. When the total is a two-digit figure, the lastfigure of the two-digit figure was to be written. The subjects were madeto resume the calculations in the next row when the supervisor called asignal after the lapse of one minute. The subjects were made to do thetest of calculation volume on each surface of the paper in 15 minutes. Aone-minute calculation operation was taken as one bout, and 15 boutswere continuously conducted without a break. The test work was carriedout in the order of a 15-minute former half test, a 10-minute intervaland a 15-minute latter half test. The test work was conducted twice(morning and afternoon) a day to confirm the difference in the workefficiency in the morning and the afternoon. The results are shown inFIG. 2.

168. The group B who worked in the odorless chamber performed thecalculations at a lower correctness ratio in the latter half test thanin the former half test (the ratio of the former being 99.6% against99.38% as that of the latter), whereas the group A who worked in thechamber filled with the fragrance showed a higher correctness ratio inthe latter half test than in the former half test (the ratio of theformer being 99.63% vs. 99.83% as that of the latter). This means thatthe subjects of the group A became mentally stabilized when they workedsmelling an aroma component in refined oil of lavender.

169. (2) Measurement with Electroencephalogram

170. The electroencephalogram (EEG) is a record of an electric activityof cerebral neurocytes. It is known that α-wave, i.e. one component ofEEG, appears in an increased amount in a state of rest wherein we areconsciously impressed with feeling mentally composed (“Influence ofAroma on Brain Function” Fragrance Journal, No. 9, 1989, pp.20-26). Therepose effect can be evaluated by measuring the amount of α waveappearing in the EEG.

171. Experiment Method

172. The experiment was carried out with 6 subjects in athermo-hygrostat.

173. The subjects were given a 20-minute rest. Then, the plasterprepared in Example 10 was applied to their foreheads and left there for3 minutes. Thereafter the amount of a wave appearing in the EEG for 3minutes was measured using a Bio amp 0523S (product of NF Kairo Co.,Ltd.). The plaster prepared in Example 10 emitted lavender fragranceimmediately after application.

174. Stated more specifically, electrodes were applied to two spots ofsubjects, foreheads to make an EEG at the two spots. After high-speedFourier transformation, the amount of a wave appearing at a frequency of8-13 Hz was taken out from the whole brain waves. In a controlexperiment, the amount of a wave appearing was determined in the samemanner as above before application of the plaster to the subject.

175. Results

176. The results are shown as compared with the results of the controlexperiment.

177. A graph A in FIG.3 shows a detailed distribution of a wave at 8 to13 HZ which was obtained by the analysis of EEG at 8 to 13 HZ. The graphA indicates that the distribution of a wave shifted to the range of 10to 12 HZ immediately after application of the plaster (poultice) to thesubject in a awakened state. This denotes that when the plaster of theinvention was applied, a soothing effect was produced. A graph B in FIG.3 shows the overall amounts of a wave appearing, in comparison, in thepresence or absence of the plaster of the invention. The figures(indices) in the graph are those for confirming the increase in theamount of a wave appearing, namely that the amount of a wave appearingwas increased by application of the plaster of the invention. A graph Cin FIG. 3 shows the proportions of α wave in the EEG in its entirety(including EEG outside 8-13 HZ region), in comparison, in the presenceor absence of the plaster of the invention. This also verifies that theamount of a wave appearing is increased by application of the plaster ofthe invention.

178. As seen from the foregoing results, the amount of α wave appearingin the EEG increases when the plaster of the invention is applied, and amentally stabilizing effect can be produced by the use thereof.

179. (3) Increase in Temperature of Peripheral Skin Surface

180. Experiment Method

181. The plaster of the invention prepared in Example 10 was applied tothe foreheads of 6 subjects in a thermo-hygrostat. The distribution oftemperature at subjects' palm of the hand was measured using athermograph.

182. In a control experiment, the subjects were kept in a relaxed statefor 20 minutes to confirm that the body temperature became constant.Thereafter, the distribution of temperature at subjects' palm of thehand was measured in a state of open eyes for 3 minutes (before rest,shown with a dotted line in a graph A) and then in a state of closedeyes for 3 minutes (after rest, shown with a solid line in the graph A).

183. Subsequently, 30 minutes later, the subjects were held again in arelaxed state. After confirming that the body temperature becameconstant, the distribution of temperature at subjects, palm of the handwas measured in a state of open eyes for 3 minutes (before rest, shownwith a dotted line in a graph B) and then in a state of closed yes for 3minutes after application of the plaster to the subjects' foreheads(after rest, shown with a solid line in the graph B).

184. The results are shown in FIG. 4.

185. The proportions (%) of area at each temperature merely increasedwithout shift of temperature distribution in a state of rest without theplaster fixed, as compared with the data before rest. On the other hand,the temperature distribution in a state of rest with the plaster fixedshifted to the right side (higher temperature) compared with the databefore rest, and the temperature on the surface of skin was elevated.When the plaster was applied (shown with a solid line in the graph B),the proportions of area at high temperatures significantly increasedcompared with the data (shown with a solid line in the graph A) when theplaster was not applied. This means that when the plaster of theinvention was used, the blood flow in the peripheral skin was increased,causing the radiation of heat from the body.

What we claim is:
 1. An adhesive cooling composition comprising apolyacrylic acid compound, a polyvalent metal component and water,wherein the content of water is 75 to 95% by weight based on the coolingcomposition.
 2. The adhesive cooling composition according to claim 1 ,wherein the content of water is 81 to 95% by weight based on the coolingcomposition.
 3. The adhesive cooling composition according to claim 1 ,wherein the composition is substantially free of a bubble component. 4.The adhesive cooling composition according to claim 1 , wherein thepolyacrylic acid compound accounts for 1 to 20% by weight and thepolyvalent metal component accounts for 0.01 to 10% by weight, of thecomposition.
 5. The adhesive cooling composition according to claim 1 ,wherein the polyacrylic acid compound has an average molecular weight of1,000,000 to 7,000,000.
 6. The adhesive cooling composition according toclaim 1 , wherein the polyacrylic acid compound is at least one memberselected from the group consisting of polyacrylic acid, sodiumpolyacrylate, potassium polyacrylate, monoethanolamine polyacrylate,diethanolamine polyacrylate, triethanolamine polyacrylate and ammoniumsalt of polyacrylic acid.
 7. The adhesive cooling composition accordingto claim 1 , wherein the polyvalent metal component is at least onemember selected from the group consisting of magnesium compounds,calcium compounds, zinc compounds, cadmium compounds, aluminumcompounds, titanium compounds, manganese compounds, cobalt compounds andnickel compounds.
 8. The adhesive cooling composition according to claim1 which further contains at least one member selected from the groupconsisting of tartaric acid, citric acid, phosphoric acid,ethylenediaminetetracetic acid and salts thereof.
 9. The adhesivecooling composition according to claim 1 which further contains apolyhydric alcohol.
 10. The adhesive cooling composition according toclaim 9 , wherein the polyhydric alcohol is at least one member selectedfrom the group consisting of glycerin, ethylene glycol, diethyleneglycol, triethylene glycol, polyethylene glycol, propylene glycol andbutylene glycol.
 11. The adhesive cooling composition according to claim1 which further contains a cellulose derivative.
 12. The adhesivecooling composition according to claim 11 , wherein the cellulosederivative is at least one member selected from the group consisting ofcarboxymethyl cellulose, hydroxymethyl cellulose, hydroxyethylcellulose, hydroxypropyl cellulose, methyl cellulose and alkali metalsalts thereof.
 13. The adhesive cooling composition according to claim 1which further contains at least one of linalool or linalyl acetate. 14.The adhesive cooling composition according to claim 13 which contains0.0005 to 0.6% by weight of linalool or 0.0005 to 0.8% by weight oflinalyl acetate.
 15. The adhesive cooling composition according to claim1 which further contains a lavender extract.
 16. The adhesive coolingcomposition according to claim 1 which is prepared by any one ofprocesses given below in (1) to (3), each process including a step ofmixing and dissolving the components of the composition and a deaeratingstep: (1) a process wherein water or an aqueous solution is deaeratedand then the other components of the composition are mixed with and/ordissolved in the deaerated solution; (2) a process wherein while wateror an aqueous solution is deaerated, the other components of thecomposition are mixed with and/or dissolved in water or aqueoussolution; or (3) a process wherein after the other components of thecomposition are mixed with and/or dissolved in water or an aqueoussolution, the obtained solution is deaerated.
 17. A laminate sheetcomprising a moisture-permeable substrate in the form of a sheet and theadhesive cooling composition of claim 1 laminated on the substrate. 18.A laminate sheet comprising a moisture-permeable substrate in the formof a sheet and the adhesive cooling composition of claim 13 laminated onthe substrate.
 19. A process for preparing the adhesive coolingcomposition of claim 1 , the process being selected from processes givenbelow in (1) to (3), each process including a step of mixing anddissolving the components of the composition and a deaerating step: (1)a process wherein water or an aqueous solution is deaerated and then theother components of the composition are mixed with and/or dissolved inthe deaerated solution; (2) a process wherein while water or an aqueoussolution is deaerated, the other components of the composition are mixedwith and/or dissolved in water or aqueous solution; or (3) a processwherein after the other components of the composition are mixed withand/or dissolved in water or an aqueous solution, the obtained solutionis deaerated.
 20. A sheet for accelerating the inducement of sleep whichcomprises the laminate sheet of claim 18 .
 21. A method of cooling aportion of subject's body, comprising the step of attaching the laminatesheet of claim 17 to the subject.
 22. A method of accelerating theinducement of sleep, comprising the step of attaching the laminate sheetof claim 18 to the subject.